Geographic atrophy of the retinal pigment epithelium is an inadequately studied form of advanced age-related macular degeneration. Geographic atrophy is responsible for a significant portion of the moderate and severe central visual loss present in the elderly population, but its evolution and progression over time is not understood. The long-term objective of the proposed study is to learn more about the natural course of geographic atrophy, and to determine whether visual function measures and funduscopic evaluation may help to predict and monitor spread. The first aim of this study is to characterize the evolution of geographic atrophy by using the photographic archives of the Wilmer Institute, and by prospectively studying fundus changes in subjects recruited for this study. Of critical interest is the rate of spread of atrophy toward the foveal center, and how this varies as a function of size of the atrophic region(s) and distance from the fovea. The second aim is to determine whether the direction or rate of spread can be predicted by visual function characteristics and funduscopic characteristics of the surrounding regions. The third aim is to study how dependent the loss of foveal function is upon the contiguous spread of atrophy. That is, if the spread could be halted, would the fovea remain relatively intact, or would it in and of itself develop atrophy with resultant visual loss? The fourth aim is to determine whether the likelihood and site of development of geographic atrophy can be predicted in fellow eyes of patients with unilateral geographic atrophy. Currently geographic atrophy is untreatable. It is anticipated that this study will identify those visual function and funduscopic characteristics important for following progression of this disorder, and thereby provide information needed for evaluating any proposed treatment regimen.